BACKGROUND: Patient-physician continuity is difficult to achieve in hospital settings because of the need to provide care continuously. The impact of hospital physician discontinuity on patient safety is unknown. OBJECTIVE: To determine the association between hospital physician continuity and the incidence of adverse events (AEs). DESIGN: Retrospective observational study using multivariable models to adjust for patient characteristics. PARTICIPANTS: Patients admitted to a nonteaching hospitalist service in a large academic hospital between March 1, 2009 and December 31, 2011. MAIN MEASURE(S): Two measures of continuity were used. The Number of Physicians Index (NPI) was the total number of unique hospitalists caring for a patient. The Usual Provider of Care (UPC) Index was the proportion of encounters with the most frequently encountered hospitalist. Outcome measures were AEs detected by automated queries of information systems and confirmed by 2 physician researchers. KEY RESULTS: Our analysis included data from 474 hospitalizations. In unadjusted models, each 1-unit increase in the NPI (ie, less continuity) was significantly associated with the incidence of 1 or more AEs (odds ratio=1.75; P<0.001). However, UPC was not associated with incidence of AEs. Across all adjusted models, neither NPI nor UPC was significantly associated with the incidence of AEs. The direction of the effect of discontinuity on AEs was also inconsistent across models. CONCLUSIONS: Hospitalist physician continuity does not appear to be associated with the incidence of AEs. Because hospital care is provided by teams of clinicians, future research should evaluate the impact of team complexity and dynamics on patient outcomes.